1. Field of the Inventions and
The present inventions relate to improvements in high speed production sheeting devices for comestible products (e.g., tortillas and tortilla chips). More specifically, the present inventions relate to sheeting devices which control the spacing of rollers used to roll a comestible product to a desired thickness.
2. Description of the Related Art
Corn tortillas and tortilla chips are cut from a sheet of corn dough, called “masa,” and then baked and/or fried. In mass production, the sheeting and cutting stages are accomplished by a tortilla sheeter.
High production tortilla sheeters feed masa from a hopper between a pair of large, stainless steel rollers which roll the masa into a sheet of substantially uniform thickness. The rollers are spaced apart in production to form a gap, known as a “pinch point gap,” through which the masa passes. The masa adheres to the surface of one of the rollers, known as the exit roller, after passing through the pinch point gap. A third roller then cuts the masa into either tortillas or tortilla chips. The third roller, known as the cutting roller, commonly has either circular shaped (for tortillas) or triangular-shaped (for tortilla chips) cutting guides positioned on the cylindrical external surface of the cutting roller. The cut tortillas or chips then are stripped from the exit roller by a wire and/or a blower, or by a similar device.
High production tortilla sheeters automate virtually every step of the sheeting and cutting process. One challenge that remains, however, is to accurately control the thickness of the masa sheet before cutting.
The consistency of corn masa commonly varies over time depending upon humidity, temperatures, granularity, and other known factors, and occasionally will contain hard kernels of corn. If the distance between the sheeting rollers is rigidly fixed, the thickness of the exiting masa sheet will change depending on the masa consistency. The consistency of the masa can also vary within the hopper, and, thus, vary across the length of the sheeting rollers. As a result, the thickness of produced tortillas or chips undesirably varies.
Prior sheeting devices included computer controlled motors driving jack screws to guide one of the rollers along a linear path to thereby control the size of the pinch point gap. For example, FIGS. 1 and 2 illustrate such a known sheeting device.
With reference to FIG. 1, the known sheeting device 10 includes a roller component 14 and a drive component 16. A lower housing 18 houses the drive component 16. The drive component 16 includes a conventional electric motor (not shown) which drives the roller component 14 via a series of common gears and chains or belts (not shown), as known in the art. A conventional pneumatic control system controls the pneumatic devices of the sheeting device 10 (e.g., a stripping wire 44 and a cutting roller 38).
The roller component 14 rests on, or is attached to, the top of the lower housing 18 and includes a hopper 22 positioned above a pair of counter rotating rollers 24, 26. The front roller 24 and the rear roller 26 are generally cylindrical. The rollers can also have a roughened surface (obtained, for example, with sandblasting). The rollers 24, 26 desirably rotate at the same speed; however, it is understood that the rollers 24, 26 can rotate at different speeds if required by specific application.
The rollers 24, 26 are positioned parallel to each other and, as shown in FIG. 2, define a pinch point 28, i.e., the point at which the rollers 24, 26 contact or nearly contact each other. In operation, the rollers 24, 26 are spaced slightly apart to form a gap between the surfaces of the rollers 24, 26 at the pinch point 28.
With continued reference to FIG. 2, the hopper 22 is positioned above the rollers 24, 26 so as to contain masa 30 between the rollers 24, 26. As noted above, the term “masa” is used to denote a corn dough which is commonly used to form tortillas and tortilla chips. However, this type of sheeting device 10 can be used with other types of comestible products, such as, for example, grain-based doughs or doughy-like food mixtures.
The rear roller can be adjusted relative to the front roller to thereby vary the spacing between the rollers 24, 26, i.e., to vary the spacing of the size of the pinch point gap 28. Thus, as is known in the art, this type of sheeting device 10 includes an electric motor-driven jack screw arrangement 38 which allows the roller 26 to be slid along the axis 32 toward and away from the roller 24.
More specifically, as shown in FIG. 2, the rear roller 26 rotates about an axis defined by the axle 34. A movable bearing plate 36 supports one end of the axle 34 and another bearing plate (not shown) supports the opposite end of the axle 34. Each of the bearing plates 36 rides in a track (not shown) supported by the frame 39. A jack screw 38 is connected to each bearing plate 36 to move the corresponding bearing plate within the track.
The axis of the track, which defines the slide axis 32, is aligned with the longitudinal axes of both rollers 24, 26 and through the pinch point 28. Thus, movement of the bearing plates 36 within their tracks moves the rear roller 26 relative to the front roller 28 to vary the size of the pinch point gap 28.
This type of sheeting device 10 also includes a controller 54 which, through the use of various sensors, controls the jack screw drive to maintain the desired thickness of the masa 42 exiting the sheeting device 10.